Vinyl phosphonate esters and method for their preparation

ABSTRACT

Vinyl phosphonate esters are provided corresponding to the following formula:   WHEREIN R is the same or different and is a C1-C12 straight or branched aliphatic group, preferably a methyl group, or a phenyl group or a halo-substituted R group. A process for their production is also disclosed. These compounds are useful as flame retardants, particularly for polyurethane foams, thermoplastic and thermoset resins and cellulosic fibers.

[ June 3, 1975 VINYL PHOSPHONATE ESTERS AND METHOD FOR THEIR PREPARATION [75] Inventor: Kyung S. Shim, lrvington, NY.

[73] Assignee: Stauffer Chemical Company,

Westport, Conn.

[22] Filed: Apr. 12, 1974 [21] Appl. No.: 460,399

[52] US. Cl 260/937; 260/2.5 AJ; 260/969;

[51] Int. Cl. C07f 9/40 [58] Field of Search 260/937, 976, 977, 969, 260/986 [56] References Cited UNITED STATES PATENTS 3,033,887 5/1962 Wadsworth et al 260/937 3,033,888 5/1962 Wadsworth et a] 260/937 3,257,480 6/1966 Hechenbleikner et al 260/937 OTHER PUBLICATIONS Pudovik et 211., Chemical Abstracts, Vol. 64 (1965), 159l6b.

Primary ExaminerLorraine A. Weinberger Assistant Examiner-Richard L. Raymond [5 7 ABSTRACT Vinyl phosphonate esters are provided corresponding to the following formula:

\ CH2 c CH2 R 10 Claims, No Drawings l VINYL PHOSPI-IONATE ESTERS AND METHOD FOR THEIR PREPARATION.

BACKGROUND OF THE INVENTION This invention relates to vinyl phosphonate esters which are usefulas' flame retardants.

Recently, there has been a great deal of interest in providing effective flame retardants for normally flammable substrates. For example, much interest is being shown in compounds which may be added to polyurethane foam to act as flame retardants without destroying the desirable physical characteristics of the foam. In addition, the flame retarding of flammable sub strates, such as textiles and thermoplastics, as well as polyurethane foam, for example, has become even more important as a result of recent governmental standards requiring that certain of these substrates be flame retarded. i

In the past, however, the flame retrading of flammable substrates has presented some problems which have not been readily overcome. For example, one problem that arises results from the generally high processing temperatures (greater than 270C.) required during the mixing and extruding of substrates such as thermoplastic fibers, like poly-(ethylene terephthalate) commonly referred to as Dacron. These high processing temperatures can cause the volatilization or thermal degradation of the therein incorporated flame retardant.

Moreover, aside from severe processing conditions, flammable substrates such as polyurethane foam, are generally subjected to ambient conditions which alone are sufficient to cause the volatilization or thermal degradation of a therein incorporated flame retardant. In addition to the loss of flame retardant activity, this degradation of the flame retardant material within the foam substrate may also result in the loss of many of the desired physical characteristics of the foam.

Regarding the flame retardant compounds themselves, while it is generally recognized that compunds which contain, for example, bromine have improved flame retardant capabilities, many of these compounds are unacceptable because of their volatility and thermal instability.

On the other hand, prior art flame retardant compounds have been developed which, while possessing the requisite thermal stability, do not possess sufficient flame retardant activity to allow for efficient use.

Accordingly, there is a need for flame retarding compounds, which while characterized by sufflcient thermal stability, also possess efficient flame retardant capability.

TECHNICAL DISCLOSURE OF THE INVENTION Therefore, it is one object of the present invention to provide novel vinyl phosphonate esters which are useful as flame retardants.

Anotherobjectof the present invention is to provide vinyl phosphonate esters which are characterized by excellent thermal stability and excellent flame retardant activity'. i I

Still another object of this invention is to provide vinyl phosphonate esters which are particularly useful as flame retardants for polyurethane foam, thermoplastics and textiles.

A further object of this invention is to provide a novel process for the preparation of the novel vinyl phosphonate esters of the present invention.

The novel vinyl phosphonate esters of the present invention are represented according to the following general formula:

wherein R is a C -C straight or branched aliphatic group, preferably a methyl group, or a phenyl group or halogenated derivatives of the foregoing R groups, preferably a bromo or chlorosubstituted R group.

The novel vinylphosphonate esters of the present invention are formed by the following process.

The first step is the reaction of a compound of the formula CH2 OH where R is defined as set forth above, with either phosphorus trichloride or phosphorus tribromide (PX where X is C1 or Br) at a temperature between about 0C and C, preferably about 60C, in a suitable organic solvent such as benzene, hexane, or chloroform. A preferred molar range of PX to the compound shown in formula II is 4:1 to 1:1. The compound which is formed has the following formula:

R CH2 c R CH Compound III is then preferably reacted with an equimolar amount of ethylene oxide in hexane at a temperature of about 0C to 100C, preferably about 40C, to

o O PX (III) form the following compound:

R CH 0 i I c P OCH -CH X R CH 0 Compound V can be converted into the vinyl ester shown in formula I, above, by means of dehydrohalogenation, preferably by the reaction of compound V in the presence ofa slight molar excess of base, such as, sodium acetate or triethylamine, and a suitable solvent, e.g.. l, 2-dichlorobenzene or tetrahydrofuran, at a temperature of about lOl30C, preferably about l l0l 15C.

As stated above, the vinyl phosphonate esters of the present invention are primarily intended for use as flame retardants for such normally flammable substrates as thermoplastics,, textiles, and for flexible or rigid polyurethane foams.

Illustrative of some of thermoplastics which can be used with the novel flame retardant of this invention are polyesters, such as poly (ethylene terephthalate); cellulose esters, such as cellulose acetate and triacetate; cellulose ethers and other cellulosics such as rayon; polyamides, such as nylon; polyolefins such as polypropylene; polyethylene oxides, polypropylene oxides; acrylics and modacrylics, i.e., fibers based on acrylonitrile copolymers; saran fibers, i.e., fibers based on vinylidene chloride copolymers; spandex fibers, i.e., fibers based on a segmented polyurethane; vinyl fibers, i.e., fibers based on vinyl chloride copolymers and the like.

Of course, although the compounds of this invention are expecially well suited as flame retardants for thermoplastics and urethane foams, they also serve as efficient flame retardants in a wide variety of other flammable substrates such as paper, wood, polystyrene, polymethyl methacrylates, urethane coatings and elastomers and other natural and synthetic textiles such as cotton, wool, silk, sisal, jute, hemp, linen and the like.

The amount of vinyl phosphonate ester which is necessary to give satisfactory flame retardance in any particular flammable substrate system will generally vary over a wide range. Usually between about 1 to about 75% based upon the weight of the substrate of the flame retardant material is employed. Preferably between about 5% to about is used. In general, any suitable known method of incorporating flame retardant materials may be utilized. For example, where thermoplastic fibers are the desired substrate, the flame retardants of the present invention may be blended with the molten polymers and extruded therewith to form the fibers. On the other hand, the flame retardant materials of this invention may be blended with the monomers prior to formation of the polymeric fiber material.

In addition, the flame retardants of the present invention may be added to textiles according to conventional procedures such as via aqueous or organic solutions which are either sprayed onto the textile or padded on" by passing the textile through the solution while the latter is being held in a tank or other suitable container.

As also indicated above, the novel vinyl phosphonate flame retardants of this invention may also be incorporated in polyurethane foams. These polyurethane foams are well known in the art and are produced by the reaction of a di or polyisocyanate or a dior polyhydroxy (polyol) compound in the presence of a blowing agent and a catalyst. The foams can be made by any of the basic techniques used in foam formation, i.e., the prepolymer technique, the semi-prepolymer technique or the one-shot process. These techniques are well EXAMPLE 1 Formation of:

Blf'CH CH O Cl CHZO/ BIS-CH In a 2 liter flask containing 458g 1.75M of dibromoneopentyl glycol and dry benzene (100ml) was added dropwise phosphorus trichloride 460g, 3.34M" at 60C. Upon completion of addition, solvent and excess phosphorus trichloride was stripped off to yield 540g of clear liquid product.

Boiling point: 0.05 mm Hg Analysis: P (theory 95%) Br 53.871 (theory 49.271) CI 9.9% (theory l0.87r)

EXAMPLE 2 Formation of dibromoneopentyl glycol chloroethylphosphite In a 500 ml flask was placed the compound from Example 1 (133g: 0.41M) and dry hexane (150 ml). While stirring vigorously ethylene oxide was added through a sintered glass gas dispersing tube. The reaction temperature was maintained at 40C using an ice bath since it was quite exothermic. Ethylene oxide was added until the reaction temperature began to drop. Yield 97%.

EXAMPLE 3 Formation of the chloroethylphosphonate ester of dibromoneopentyl glycol In a 250 ml flask was placed 200 g of the compound from Example 2 and 0.1g iodomethane. The resulting mixture was heated to 192C and held at that temperature for 30 minutes to give 198g of clear liquid.

Analysis P 9.671 (theory 8.971) Br 37.97! (do. 43.3%) CI 8.6% (do. 9.671)

EXAMPLE 4 Formation of the vinylphosphonate ester of dibromoneopentyl glycol Into a 250 ml flask was placed the compound from Example 3 (92g: 0.25M), O-dichlorobenzene ml) and sodium acetate (30g: 0.35M). The resulting mixture was heated to l 1 C and kept at that temperature over a period of 5 hours, after which the insoluble salts were separated through a filter and the organic layer was washed with water, dried over magnesium sulfate and stripped of solvent to give yellowish oil Analysis:

P 8.4% (Theory 8.69? Br 42.87: (Theory 44.6)?

EXAMPLE 5 The product from Example 4 was used in formulating a polyurethane foam utilizing the following neogents:

AMOUNT REAGENT (1N GRAMS) Polyol (Voronol 3000) 100 Example 4 Product 15 Silicone L-520 Surfactant 1.5 Water 3.6 Amine Catalyst (A-l) 0.12 Dahco 33 LV 0.35 Blowing Agent (Cl CF) 3.0 DMF 3.0 Tm (Stannous Octoate) 0.60 Toluene Diisocyanate 45.8

The rise time of the foam was 120 seconds ambient temperature. The foam that was produced weighed 6.3 89, had a density of 2.03 lbs/ft and had an average air flow of 4.3 ft 3/min.

When three samples of the foam were tested for flame retardancy using ASTM-l692 the samples selfextinguished between 80 and 95 seconds after 60-70 mm of foam had burned. The average burn rate was 0.72 mm/sec. for all three samples.

A number of compounds having the following structural formula:

0 Br CH CH 0 P R Br CH2 CH2 O where R is defined in the Table below were incorpo rated in the polyurethane foam formulation set forth above and were tested for flame retardancy. The table sets forth the burn rate:

wherein R is selected from the group consisting of the straight and branched C -C alkyl groups, the phenyl group, the bromo and chloro substituted C -C 12 alkyl groups, and the bromo and chloro substituted phenyl groups.

2. Compounds of the formula set forth in claim 1 wherein the R group is selected from the group consisting of methyl and the bromo and chloro substituted methyl groups.

3. A compound of the formula set forth in claim 1 wherein R is a bromomethyl group.

4. A process for forming compounds as set forth in claim 1 which comprises:

a. reacting a compound of the formula with a compound selected from the group consisting of phosphorus trichloride and phosphorus tribromide to form a compound having the formula:

where X is selected from the group consisting of chlorine and bromine and R is as defined in claim 1;

b. reacting the product formed in step (a) with ethylene oxide to form a compound having the formula:

R 0H2 o c aocazca x R/ CH2 o where R and X are as defined above;

c. reacting the product of step (b) with an Arbuzov rearrangement catalyst to form an Arbuzov rearrangement product having the formula:

R CH O O 2 u C P-CH CH X where R and X are as defined above; and

d. dehydrohalogenating the product of step (c) with a base to form the compounds claimed in claim 1.

5. A process as claimed in claim 4 wherein the reaction in Step (a) is carried out at a temperature of about 0C to C.

6. A process as claimed in claim 4 wherein the reac tion in Step (b) is carried out at a temperature of about 0C to 100C.

7. A process as claimed in claim 4 wherein the reaction with the Arbuzov rearrangement catalyst is carried out at a temperature of above about 160C.

8. A process as claimed in claim 4 wherein the Arbuzov rearrangement catalyst is selected from the group consisting of the C -C alkyl halides, the aryl halides, the alkali metal halides and iodine.

9. A process as claimed in claim 4 wherein about 0.01% to 0.3% by weight of Arbuzov rearrangement catalyst is used.

10. A process as claimed in claim 4 wherein the reaction in Step (d) is carried out at a temperature of about 100C to C.

UNITED STATES PATENT AND TRADEMARK OFFICE ermr m PATENT N0. 3,887,656

DATED June 3, 1975 mvemoms) y q Shim it is certified that aim appears iv the ab0veideniified eaten? and that said Letters Patent are hereby corrected as shown below:

C010 1, line 41, change "compunds" to compounds Col. 2, line 55, change "arrangement" to rearrangement C010 3, line 12, delete one of the commas after "thermoplastics"; Co1.. 3, line 62, change "or" after "polyisocyanate" to and C01,, 4, line 20, change (100 ml) to (1000 m1) C01,, 4, line 66, change (100 m1) to (110 m1) igncd and fiealcd this ninth of September 1975 [SEAL] Arrest:

RUTH C. MASON c. MARSHALL DANN Altesllng ()jfzcer ('mmnissimwr ufluu'ms and Trademarks 

1. COMPOUNDS OF THE FORMULA
 1. Compounds of the formula
 2. Compounds of the formula set forth in claim 1 wherein the R group is selected from the group consisting of methyl and the bromo and chloro substituted methyl groups.
 3. A compound of the formula set forth in claim 1 wherein R is a bromomethyl group.
 4. A process for forming compounds as set forth in claim 1 which comprises: a. reacting a compound of the formula
 4. A PROCESS FOR FORMING COMPOUNDS AS SET FORTH IN CLAIM 1 WHICH COMPRISES: A. REACTING A COMPOUND OF THE FORMULA
 5. A process as claimed in claim 4 wherein the reaction in Step (a) is carried out at a temperature of about 0*C to 100*C.
 6. A process as claimed in claim 4 wherein the reaction in Step (b) is carried out at a temperature of about 0*C to 100*C.
 7. A process as claimed in claim 4 wherein the reaction with the Arbuzov rearrangement catalyst is carried out at a temperature of above about 160*C.
 8. A process as claimed in claim 4 wherein the Arbuzov rearrangement catalyst is selected from the group consisting of the C1-C9 alkyl halides, the aryl halides, the alkali metal halides and iodine.
 9. A process as claimed in claim 4 wherein about 0.01% to 0.3% By weight of Arbuzov rearrangement catalyst is used. 